In a common type of glassware forming machine, a gob of molten glass is formed, at a blank station, into a parison. The parison is transferred to a blow station at which it is blown into a container, and the blown container is then removed from the machine to a cooling station and thence to a conveyor.
The parison, when it is transferred from the blank station to the blow station, and the blown container when it is moved from the blow station to the cooling station, are readily deformable. Consequently, movement of the parison and the blown container has to be very carefully controlled to avoid distortion or damage, while at the same time such movement needs to be carried out as quickly as possible to obtain the maximum output from the machine. An invert mechanism carries the parisons of hot glass from the blank station through about 180.degree. about a horizontal axis to the blow station.
A take out mechanism picks the blown containers up from the blow station and moves them, in a vertical orientation, through an arcuate path to the cooling station.
Critical control of the movement of the take out mechanism and of the invert mechanism is necessary to avoid distortion of the still soft glass due to any sudden uncontrolled motion.
There are certain other mechanisms in a glassware forming machine where, for other reasons, critical control of the movement of a mechanical member is desirable. An example of this is the movement of the plunger in a parison forming operation, which needs to be closely controlled to avoid the development of excessive pressure on the glass. Other mechanisms will benefit from critical control of their movement, in that faster and more precise operation and a longer life can thus be obtained.